Apparatus for making wire spirals



April 24, 1962 J. D. FOKKINGA 3,031,006

APPARATUS FOR MAKING WIRE SPIRALS Filed Oct. 25, 1958 2 Sheets-Sheet 1 A A m. H

a2 a s M/VQUTM? Jam/v3 I-BKK Q April 24, 19 2 J- D. FOKKINGA APPARATUS FOR MAKING WIRE SPIRALS 2 Sheets-Sheet 2 Filed Oct. 23, 1958 United States Patent lands Filed Oct. 23, 1958, Ser. No. 769,261 Claims priority, application Netherlands Oct. 29, 1957 7 Claims. (Cl. 153-67) The invention relates to an apparatus for making wire spirals, in particular incandescent spirals for incandescent lamps, discharge tubes and similar apparatuses. The Dutch patent specification 17,132 describes an arrangement for making wire spirals having substantially aligned straight ends, which spirals are wound by means of a Winding head via a wire guiding member onto a mandrel due to the mutual rotation of the winding head and the wire guiding member, said mandrel being adapted to be retracted when the winding is finished. It has been found that, with this known arrangement, in consequence of the strong friction of the wire in the mouthpiece forming the outlet of the wire guiding member, the chances are that the wire that is to be coiled may get damaged. This danger is particularly to be feared in the manufacture of so-called double-coiled incandescent spirals, wherein the wire from which is started consists of a thin tungsten wire that is wound round a core Wire, which is removed, in particular in a chemical way, when the double spiral is finished. The invention has for its object an arrangement of the type above referred to, whereby the possibility of damaging the wire to be coiled is reduced to a minimum.

According to the invention the wire guiding member is arranged for swinging movement with respect to the mandrel, in such a way, that during the winding of the spirals the wire is fed to the mandrel through the mouthpiece of the wire guiding member at an angle with respect to the axial direction of the mandrel which is approximately equal to the angle of the Winding pitch. The present invention has namely shown that the damage experienced by the wire of the known arrangement must be substantially ascribed to the unfavorable angle at which the mouthpiece of the wire guiding member is placed. This angle, which is about 0, deviates considerably from the angle of the winding pitch, so that, between the mouthpiece of the wire guiding member and the mandrel, the wire must be strongly bent over some sort of auxiliary guiding member. 'Due to the fact that the wire guiding member is mounted for swinging movement, it is possible, during the winding of the spirals, to make said angle substantially equal to the angle of the winding pitch, so that the friction with respect to the auxiliary guiding member, and consequently the risk of damage, is considerably reduced. According to the invention it is even possible to completely leave out such an auxiliary guiding member if the said angle of the wire guiding member is entirely equal to the angle of the Winding pitch. It is, however, preferred to choose said angle of the wire guiding member slightly smaller than the angle of the winding pitch in order to create some tensile stress, which furthers the regular winding of the Wire round the mandrel. In this case it is preferable to lead the wire between the mouthpiece of the wire guiding member and the mandrel along a guiding pin that is disposd coaxially with respect to the axis: of rotation of the wire guiding member.

After a spiral has been made in an apparatus according to the invention, the straight extremity thereof, which adjoins the wire guiding member, must, by turning this wire guiding member backwards, be brought in alignment with the straight extremity of the wire spiral, which extremityis located in the winding head. Due to the elasticity of the material of the wire there is a possibility that the first-named extremity will spring back so that the desired direction gets lost. In order to avoid this drawback it is recommended, after a spiral has been completed, to swing the wire guiding member back, beyond the position in which the mouthpiece of the winding head and the mouthpiece of the wire guiding member are extending substantially in alignment with respect to each other. In consequence thereof the relative extremity is bent a little too far, but, due to the elasticity, the extremity will thereafter assume the desired position.

In a preferred embodiment of the apparatus according to the invention the spindle round which the wire guiding element is swinging is supported by a slide that is adapted to move in parallel with the longitudinal direction of the mandrel. A displacement of the slide is preferably carried out by means of wedges adapted to be slidably displaced in transverse direction with respect to the slide. One wedge can herewith bring about the displacement during the Winding and the other wedge can eflfect the displacement while the straight ends of the spirals are being made.

The removal of the wound spiral from the mandrel may, according to the invention, be facilitated by turning the Winding head back through a small angle after the winding operation is finished in order to release the just wound spiral with respect to the mandrel. Said turning back is preferably brought about by means of a cam disc connected with the winding head and a roll that is pressing against it, which roll, by snapping into a recess of the cam disc, adjusts at the same time the winding head in alignment with the mouthpiece of the wire guiding memher.

The invention will now be further explained with reference to an example of execution, represented in the drawing.

FIGURES 1a through 1h respectively show schematically the relative positions of the winding head and the wire guiding member in the various successive working phases.

FIGURE 2 shows a front view belonging to FIGURE 1b in which a part of the slide carrying the swingable wire guiding member is indicated.

FIGURE 3 is a plan view of the apparatus in which only the most important parts are indicated.

FIGURE 4 gives a cross section through the line IV-IV of FIGURE 3.

FIGURE 5 gives a cross section through the line V-V of FIGURE 3.

In the FIGURES the numeral 1 designates the winding head, which is provided with a channel 2 for receiv ing the free extremity of the wire 6 that is to be coiled. In the winding head a slidably movable mandrel 4 is provided as well as the wire clamping member 3 for securing the free end of the wire 6. The wire guiding member 5 is provided with a channel 5 for passing the wire 6 through. The wire can be fixed relatively to the wire guiding member 5 by means of the wire clamping member 7. 9 is the hollow spindle of the Wire guiding member 5, in which the guiding pin 8 is coaxially incorporated. 10 is the part of the slide, adapted to be moved in parallel relation to the axial direction of the mandrel 4, which part carries the hollow spindle 9. The swinging movement of the wire guiding member 5 is brought about by means of the lever 14, which is rigidly secured to the hollow spindle 9 carrying the wire guiding member 5. The numeral 12 designates the cutters for cutting the finished spiral 11.

As may appear from FIG. 1a the working cycle starts with the winding head 1 and the wire guiding member 5 spaced some distance apart from each other, the channels 2 and being in alignment with each other and the wire 6 being fixed with respect to the wire guiding member by means of the wire clamping member 7. FIG. 1b shows how thereafter the wire guiding member 5 is brought into the immediate neighborhood of the winding head 1 and the free extremity of the wire 6 is inserted into the channel 2 of the winding head. According to FIG. the wire clamping element 3 is then caused to engage the wire 6 while at the same time the wire guiding member 5 is caused to make a swinging movement and the wire clamping member 7 is released, after which the winding head .1 starts rotating in the direction indicated by the arrow.

The wire guiding member 5 assumes now a position in which the channel 5' forms an angle 1) with the axial direction of the mandrel 4; see FIG. 1d. In this figure the winding pitch angle a is also indicated. The angle b is chosen a little smaller than the angle a so that the wire 6, that is to be wound to form a spiral 11, passes the guiding pin 8 with some friction. After the spiral 11 has reached the desired number of windings (the number of revolutions of the winding head required herefor is adjusted in a manner known per se) so that the position of FIG. 1d is reached, the winding head 1 is arrested in a position in which the channel 2 has rotated too far through a predetermined angle in dependency on the number of windings applied and the nature of the material the wire is made of. According to FIG. la the winding head 1 is then turned back somewhat until it reaches the position of FIG. la. At the same time the wire guiding member 5 is swung against a plate spring 34 beyond the position in which the channel 2 of the winding head and the channel 5' of the wire guiding member 5 are forming a straight line. In consequence hereof the wire 6 is bent round the guiding pin in such a way that the spiral 11 with the straight extremities is entirely expanded when the wire guiding member has been brought into the position indicated in FIG. 1 This position is fixed by means of a resilient cam 35, which is adapted to be retracted on behalf of the swinging of the wire guiding member 5 according to FIG. 1c, e.g. by an electromagnet. Thereupon the wire guiding member 5 is further retracted as shown in FIG. lg, the wire clamping element 3 remaining applied in the beginning and the wire clamping element 7 being released.

Thereupon the wire clamping member 3 is released and the wire clamping member 7 is applied while the wire guiding member 5 is further displaced to the right, as shown in FIGURE 1h. The finished wire spiral 11 is then cut off by the cutters 12, whereupon the cycle is repeated.

As may be seen from FIGURES 3 and 4 the reciprocating movement of the slide 10 carrying the swingable wire guiding member 5, is eifected by two Wedges 15 and 15, carried by bars 16 and 17 which are mounted for slidable movement in transverse direction with respect to the sliding member 19. These bars are standing under the influence of step back springs 18 and 19 and can, against the action of these springs, be slidably moved by means of tension rods 20 and 21 on behalf of the moving of the slide 10 to the right. Said tension rods may be actuated by electromagnets, which, by means of contacts of a program-control switch, are switched in at predetermined moments of the cycle. The wedges 15, 15 enter into engagement with rolls 22, 23 connected with the slide 10. The wire clamping member 3 is operated by a tumbler-lever 24 which is caused to swing by means of a driving rod 25. The wire clamping member 7 is operated by a two-armed lever 26 that is carried by the slide and has a driving rod 27. The rods and 27 and the cam 35 are connected with electromagnets which, at due moments of the working cycle, are switched in and put by contacts of said program control switch.

Of course the displacing of the slide to the right, i.e. during the winding of a spiral, must take place at a 4 predetermined rate in order to obtain the desired winding pitch. This rate is controlled by a braking device 28, which, through a pinion 29, engages a toothed rack 30 of the rod 16.

The backward turning of the winding head 1 from the position id to the position 12 is eifected by means of a profile disc 31 (see FIGURE 5) with pressure roll 32. When the winding head 1 is arrested in the position of FIG. 5, the roll 32 is moved to engage the cam edge of recess 33 and cause a backward turning of the disc 31. As a result Winding head 1 also reverses in the direction of the arrow drawn in dotted lines after which the roll 32 snaps into the recess 33 of the disc 31 stopping the head 1 in its FIG. 1e position. The roll 32 is moved by lever 36 which like other levers previously described are actuated by electromagnets programmed to operate in exact time sequence by the program control switch previously mentioned. The backward turning of head 1 through the described small angle expands the spiral slightly and loosens it with respect to the mandrel sufficiently to enable easy separation of the spiral from the mandrel at a subsequent time in the operation cycle.

What I claim is:

1. Apparatus for making wire spirals having straight extremities extending substantially in alignment with each other, comprising an axially movable and retractable mandrel, a winding head rotatable about said mandrel, a passage in said winding head and releasable means for clamping one end of the wire in said passage during rotation of the winding head, a wire guiding member pivotably mounted about an axis transverse to said mandrel and supported for slidable movement parallel to said mandrel, means for pivotally moving said wire guiding member to a winding position in which the guiding member feeds wire to the mandrel at an angle approximately equal to the angle of the winding pitch during rotation of the winding head, means for slidably moving said guiding member to form a wire spiral about the mandrel, and means for pivotally moving said Wire guiding member to a spiral terminating position in which the wire in the guiding member is held aligned with said passage in the winding head after completion of the winding of the spiral.

2. Apparatus according to claim 1 wherein said guiding member when in said winding position feeds Wire to the mandrel at an angle slightly less than the angle of the winding pitch.

3. Apparatus according to claim 2, wherein said guiding member is provided with a guiding pin against which the wire is fed from said member to the mandrel, said guiding pin being arranged coaxial with said pivot axis of the guiding member.

4. Apparatus according to claim 1, wherein means are provided for pivotally moving said wire guiding member back through an angle greater than the angle of the winding pitch to an intermediate position in which the wire in the guiding member is stretched after completion of the winding of the spiral and before operation of said means for moving the wire guiding member to said spiral terminating position. 7

5. Apparatus according to claim 1, wherein means are provided for reversing the rotation of said winding head through a small angle after winding of the spiral for expanding the just wound spiral relatively to the mandrel.

6. Apparatus according to claim 5, wherein said means for reversing the winding head comprises a cam disc having a recess and connected to the winding head, and a roll pressing against said disc, said roll being adapted to turn the winding head and snap into said recess whereby to adjust the angular position of the winding head to align the passage in the winding head with the wire held in the guiding member in its terminating position.

7. Apparatus according to claim 1, wherein said means for slidably moving said guiding member parallel to the mandrel eirects movement of said guiding member at one 5 rate while in its winding position, and at a different rate 2,439,893 While in its spiral terminating position. 2,758,629 2,777,351 References Cited in the file of this patent UNITED STATES PATENTS 5 379,393 Harvey Mar. 13, 1888 60-808 434,804 Quiggin Aug. 19, 1890 239,832 952,582 Ritter Mar. 22, 1910 562,828

6 Iden Apr. 20, 1948 Lewis Aug. 14, 1956 Johnson Jan. 15, 1957 FOREIGN PATENTS Germany Jan. 29, 1892 Germany Oct. 21, 1911 France Sept. 15, 1923 

